#!/bin/ksh -x
#
# /etc/qemu-bridge:	Script to take a TAP passed in as
#			a parameter and bridge it to an
#			interface.
#
# Parameters:		$1	-	The TAP device
#			[$2]	-	Network interface to bridge TAP to
#					otherwise assume the first interface
#
#
# Requires the bridge package from 
# http://www.whiteboard.ne.jp/~admin2/tuntap/#bridge
# 
# Configuration Section:
#
#  PRIMARY_INTERFACE should be set if you are using this directly from
#  qemu, and you don't want to let the automatic detection code define
#  the interface.  It will be overridden if you pass in a defined
#  interface using the sol_qemu_bridge wrapper.
#
#  BRDGADM_EXE is the location of the brdgadm command. by default,
#  it installs in /usr/local/bin.  It only moves, if you move it
#  as the configure script doesn't accept --prefix=<localation>
#
PRIMARY_INTERFACE=
BRDGADM_EXE=/usr/local/bin/brdgadm
#
################################################################
#
# Security.
#
# use RBAC to create a limited role which allows you to create the bridge
#
# If you can't do RBAC, you have to use sudo
#
# sudoer's entry: <user> ALL={ALL} NOPASSWD: /usr/local/bin/brdgadm
#
SUDO_EXE=/opt/csw/bin/sudo
#
BRDGADM="${SUDO_EXE} ${BRDGADM_EXE}"
#
#################################################################

#
# $1 = tap0, tap1, ...

if [ -z "$1" ]; then
	echo "Usage: $0 interface [bridge interface]"
	exit 1
else
	TAP_INTERFACE="$1"
fi
#
# we're setting the interface we want to bridge the tap to.
# do some basic sanity checking. If they botch the interface,
# just allocate one that exists.
#
if [ -n "$2" ]; then
	PRIMARY_INTERFACE="`/usr/sbin/ifconfig -a | /usr/bin/egrep -v '^[ 	]|^lo0:' | /usr/bin/cut -f1 -d: | /usr/bin/grep $2 2> /dev/null | /usr/bin/awk '{ print $1 }'`"
fi
#
# Figure out which interface to test for from existing bridges
# IE, we have to delete any bridge that contains either the
# defined TAP or the defined PRIMARY_INTERFACE
#
if [ -n "${PRIMARY_INTERFACE}" ]; then
	# Define the a variable to check existing interface is bridged
	TEST_INTERFACE="${PRIMARY_INTERFACE}"
else
	# Define the a variable to check existing tap is bridged
	TEST_INTERFACE="${TAP_INTERFACE}"
fi
#
# Get the list of bridged interfaces
#
BRIDGED=`${BRDGADM} -l 2> /dev/null | /usr/bin/egrep -v "^List of the interfaces|^--------" 2> /dev/null`
if [ -n "${BRIDGED}" ]; then
	ORIG_INT="`/usr/bin/echo ${BRIDGED} | /usr/bin/awk '{ print $1 }'`"
	#
	# if the defined interface is part of a bridge group, or
	# the new tap is already part of a bridge group,
	# delete the bridge before we create it, otherwise
	# the creation of the bridge will fail.
	#
	if [ "${ORIG_INT}" = "${TEST_INTERFACE}" ]; then
		for i in ${BRIDGED}
		do
			${BRDGADM} -d $i
			if [ $? -ne 0 ]; then
				echo "deletion of interface $i from the bridge failed, rc=$?"
				exit 1
			fi
		done
	fi
fi
#
# If an interface to bridge to is undefined, try and make a good guess
# at the first interface that isn't lo0.
#
if [ -z "${PRIMARY_INTERFACE}" ]; then
	PRIMARY_INTERFACE="`/usr/sbin/ifconfig -a | /usr/bin/egrep -v '^[ 	]|^lo0:' | /usr/bin/cut -f1 -d:| /usr/bin/awk '{ print $1 }'`"
fi
#
# Create the new bridge
#
${BRDGADM} -a ${PRIMARY_INTERFACE}
${BRDGADM} -a ${TAP_INTERFACE}